Electrochemical battery-type supercapacitor based on chemosynthesized Cu₂SAg₂S composite electrode

Pawar, Sachin A.,Patil, Dipali S.,Shin, Jae Cheol Elsevier 2018 ELECTROCHIMICA ACTA Vol.259 No.-

<P><B>Abstract</B></P> <P>Metal sulfide-based electrochemical supercapacitors are widely attracted owing to their high electrical conductivity and excellent redox properties. Moreover, the fabrication of high performance supercapacitors based on simple and cost effective chemical routes is in strong demand. In this study, a facile and low cost, successive ionic layer adsorption and reaction (SILAR) technique is used to form a Cu<SUB>2</SUB>SAg<SUB>2</SUB>S composite electrode on nickel foam in a common sulfur source beaker for both copper and silver with less time and material consumption. The electrodes exhibits a high specific capacity of 772 Cg<SUP>−1</SUP> at a scan rate of 10 mVs<SUP>−1</SUP> compared to pristine Cu<SUB>2</SUB>S and Ag<SUB>2</SUB>S and shows excellent cycling stability with a capacity retention of 89% after 2000 CV cycles. This is attributed to the highly conductive and reactive Ag<SUB>2</SUB>S layer, which simplifies the diffusion of electrolyte ions to access active Cu<SUB>2</SUB>S materials and facilitates rapid electron transport to achieve high-performance battery-type supercapacitors. This study provides a simple and cost-effective approach to the fabrication of high-performance battery-type supercapacitors based on highly conductive and earth-abundant, copper-based composite metal sulfide electrodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu<SUB>2</SUB>SAg<SUB>2</SUB>S composite electrode is synthesized by SILAR technique. </LI> <LI> A common sulfur source beaker is kept for both copper and silver in SILAR. </LI> <LI> Cu<SUB>2</SUB>SAg<SUB>2</SUB>S exhibited a specific capacity of 772 Cg<SUP>−1</SUP> at a scan rate of 10 mVs<SUP>−1</SUP>. </LI> <LI> An excellent cycling stability with a capacity retention of 89% is observed. </LI> <LI> Efficient supercapacitor fabrication by simple and cost effective chemical route. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A facile and low cost, successive ionic layer adsorption and reaction (SILAR) technique was used to form a Cu<SUB>2</SUB>SAg<SUB>2</SUB>S composite electrode on nickel foam in a common sulfur source beaker for both copper and silver with less time and material consumption.</P> <P>[DISPLAY OMISSION]</P>

Hexagonal sheets of Co₃O₄ and Co₃O₄-Ag for high-performance electrochemical supercapacitors

Pawar, Sachin A.,Patil, Dipali S.,Shin, Jae Cheol Elsevier 2017 Journal of industrial and engineering chemistry Vol.54 No.-

<P><B>Abstract</B></P> <P>Hexagonal sheets of Co<SUB>3</SUB>O<SUB>4</SUB> on nickel foam were synthesized by a facile, economical, scalable, and one pot hydrothermal method for supercapacitor studies. The electrical conductivity and catalytic activity were enhanced through the decoration of Co<SUB>3</SUB>O<SUB>4</SUB> by silver (Ag) nanoparticles using a simple chemical approach. The hexagonal sheets served as an excellent backbone together with the Ag nanoparticles, which gave the composites a superior specific capacitance of 958Fg<SUP>−1</SUP> and an energy density of 0.203kWhkg<SUP>−1</SUP>. The electrode exhibited excellent cycling stability with a capacitance retention of 104% after the initial 1000 CV cycles with a maximum specific capacitance 996Fg<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hexagonal sheets of Co<SUB>3</SUB>O<SUB>4</SUB> electrode is synthesized by hydrothermal route. </LI> <LI> AgNPs are decorated on Co<SUB>3</SUB>O<SUB>4</SUB> by a simple chemical approach. </LI> <LI> Effect of AgNPs treating time on the performance of supercapacitors is studied. </LI> <LI> Co<SUB>3</SUB>O<SUB>4</SUB>-Ag exhibited a specific capacitance of 958Fg<SUP>−1</SUP> at a scan rate of 10mVs<SUP>−1</SUP>. </LI> <LI> An excellent cycling stability with a capacitance retention of 104% is observed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A versatile hydrothermal technique is employed to synthesize hexagonal sheets of Co<SUB>3</SUB>O<SUB>4</SUB>. Silver (Ag) nanoparticles (NPs) were decorated on the hexagonal sheets of Co<SUB>3</SUB>O<SUB>4</SUB> by a simple chemical route. Effect of AgNPs treating time on the performance of supercapacitors is studied.</P> <P>[DISPLAY OMISSION]</P>

Quantum dot sensitized solar cell based on TiO₂/CdS/Ag₂S heterostructure

Pawar, Sachin A.,Patil, Dipali S.,Kim, Jin Hyeok,Patil, Pramod S.,Shin, Jae Cheol Elsevier 2017 Optical Materials Vol.66 No.-

<P><B>Abstract</B></P> <P>Quantum dot sensitized solar cell (QDSSC) is fabricated based on a stepwise band structure of TiO<SUB>2</SUB>/CdS/Ag<SUB>2</SUB>S to improve the photoconversion efficiency of TiO<SUB>2</SUB>/CdS system by incorporating a low band gap Ag<SUB>2</SUB>S QDs. Vertically aligned TiO<SUB>2</SUB> nanorods assembly is prepared by a simple hydrothermal technique. The formation of CdS and Ag<SUB>2</SUB>S QDs over TiO<SUB>2</SUB> nanorods assembly as a photoanode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The synthesized electrode materials are characterized by XRD, XPS, field emission scanning electron microscopy (FE-SEM), Optical, solar cell and electrochemical performances. The results designate that the QDs of CdS and Ag<SUB>2</SUB>S have efficiently covered exterior surfaces of TiO<SUB>2</SUB> nanorods assembly. A cautious evaluation between TiO<SUB>2</SUB>/CdS and TiO<SUB>2</SUB>/CdS/Ag<SUB>2</SUB>S sensitized cells tells that CdS and Ag<SUB>2</SUB>S synergetically helps to enhance the light harvesting ability. Under AM 1.5G illumination, the photoanodes show an improved power conversion efficiency of 1.87%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 7.03 mA cm<SUP>−2</SUP> which is four fold higher than that of a TiO<SUB>2</SUB>/CdS system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> QDSSC fabrication using 1D TiO<SUB>2</SUB> nanostructures. </LI> <LI> High surface area for QDs loading. </LI> <LI> Strong absorption in the visible regime for TiO<SUB>2</SUB>/CdS/Ag<SUB>2</SUB>S. </LI> <LI> The QDSSC show improved photocurrents. </LI> <LI> High power conversion efficiency of 1.87%. </LI> </UL> </P>

Efficient supercapacitor based on polymorphic structure of 1T′-Mo₆Te₆ nanoplates and few-atomic-layered 2H-MoTe₂: A layer by layer study on nickel foam

Pawar, Sachin A.,Kim, Donghwan,Lee, Rochelle,Kang, Sang-Woo,Patil, Dipali S.,Kim, Tae Wan,Shin, Jae Cheol Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.371 No.-

<P><B>Abstract</B></P> <P>Te-based transitional metal dichalcogenides (TMDs) as supercapacitors are gaining substantial attention with a few reports. The integration of 1T′-Mo<SUB>6</SUB>Te<SUB>6</SUB> nanoplates (NPs) into few-atomic-layered two dimensional (2D) 2H-MoTe<SUB>2</SUB> thin film has not been realized in supercapacitive studies. Herein, we demonstrate the growth of 1T′-Mo<SUB>6</SUB>Te<SUB>6</SUB> NP/2H-MoTe<SUB>2</SUB> thin film polymorphic structure through metal organic chemical vapor deposition (MOCVD) on Si/SiO<SUB>2</SUB> and thereby, the successful transfer of these polymorphic structure on a flexible nickel (Ni) foam current collector by simple chemical etching protocol for high performance supercapacitors. A layer by layer study of the Mo<SUB>6</SUB>Te<SUB>6</SUB>/MoTe<SUB>2</SUB> polymorphic structure is carried out by varying the number of transfer layers on the Ni foam. The resultant supercapacitors demonstrate a three-fold enhancement in areal capacitance (1542 mFcm<SUP>−2</SUP> at 10 mVs<SUP>−1</SUP>) compared to a single layer transferred electrode, together with remarkable electrochemical stability (96%) and high energy density (140.36 mWcm<SUP>−2</SUP> at 4 mA). These supercapacitors outperform the TMD-based (Te-based) supercapacitors presented in the past, demonstrating the high potential for their application in energy conversion devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Integration of 1T′-Mo<SUB>6</SUB>Te<SUB>6</SUB> NP/2H-MoTe<SUB>2</SUB> thin film polymorphic structure. </LI> <LI> Transfer of polymorphic structure on a flexible nickel (Ni) foam current collector. </LI> <LI> A three-fold enhancement in areal capacitance (1542 mFcm<SUP>−2</SUP> at 10 mVs<SUP>−1</SUP>). </LI> <LI> The specific capacitances of 3816 Fg<SUP>−1</SUP> at 10 mVs<SUP>−1</SUP> for optimized electrode. </LI> <LI> An excellent cycling stability with a capacitance retention of 96% is observed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The growth of 1T′-Mo<SUB>6</SUB>Te<SUB>6</SUB> NP/2H MoTe<SUB>2</SUB> thin film polymorphic structure through MOCVD on Si/SiO<SUB>2</SUB> and thereby, the successful transfer of these polymorphic structure on flexible nickel (Ni) foam current collector by simple chemical etching protocol for high performance supercapacitor is demonstrated.</P> <P>[DISPLAY OMISSION]</P>

Transition of hexagonal to square sheets of Co3O4 in a triple heterostructure of Co3O4/MnO2/GO for high performance supercapacitor electrode

Sachin A. Pawar,Dipali S. Patil,신재철 한국물리학회 2019 Current Applied Physics Vol.19 No.7

Cobalt oxide and manganese oxides are promising electrode materials amongst the transition metal oxides (TMOs) for pseudocapacitors. The lack of reversibility and deterioration of capacitance at higher current densities is major flaw in Co3O4 as an electrode for supercapacitor while MnO2 suffers from low electrical conductivity and poor cycling stability. It is inevitable to bridge the performance gap between these two TMOs to obtain a high performance supercapacitor based on environmental benign and earth abundant materials. Herein, we fabricated a hybrid triple heterostructure high-performing supercapacitor based on hexagonal sheets of Co3O4, MnO2 nanowires and graphene oxide (GO) to form a composite structure of Co3O4/MnO2/GO by all hydrothermal synthesis route. The Co3O4 square sheets serves as an excellent backbone with good mechanical adhesion with the current collector providing a rapid electronic transfer channel while the integrated nanostructure of MnO2 NW/GO permits more electrolyte ions to penetrate capably into the hybrid structure and allows effective utilization of more active surface areas. A triple heterostructured device exhibits a high areal capacitance of 3087 mF cm−2 at 10 mV s−1 scan rate along with the exceptional rate capability and cycling stability having capacitance retention of ∼170% after 5000 charge/discharge cycles. The TMOs based pseudocapacitor with the conducting scaffolds anchoring based on graphene derivatives like this will pave an encouraging alternatives for next generation energy storage devices.

MnO2-Graphene Oxide-PEDOT:PSS Nanocomposite for an Electrochemical Supercapacitor

Dipali S. Patil,Sachin A. Pawar,신재철,김효진 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.8

A ternary nanocomposite with poly (3,4 ethylene dioxythiophene:poly(styrene sulfonate) (PEDOT:PSS)-MnO2 nanowires-graphene oxide (PMn-GO) was synthesized by using simple chemical route. The formation of the nanocomposite was analyzed by using X-ray diffraction and X-ray photoelectron spectroscopy. Field-emission scanning microscopy (FESEM) revealed the formation of MnO2 nanowires and graphene oxide nanosheets. The highest specific capacitance (areal capacitance) of 841 Fg −1 (177 mFcm −2) at 10 mVs −1 and energy density of 0.593 kWhkg −1 at 0.5 mA were observed for PMn-GO, indicating a constructive synergistic effect of PEDOT:PSS, MnO2 nanowires and graphene oxide. The achieved promising electrochemical characteristics showed that this ternary nanocomposite is a good alternative as an electrode material for supercapacitor.

A Simple Aqueous Precursor Solution Processing of Earth-Abundant Cu₂SnS₃ Absorbers for Thin-Film Solar Cells

Suryawanshi, Mahesh P.,Ghorpade, Uma V.,Shin, Seung Wook,Pawar, Sachin A.,Kim, In Young,Hong, Chang Woo,Wu, Minhao,Patil, Pramod S.,Moholkar, Annasaheb V.,Kim, Jin Hyeok American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.18

<P>A simple and eco-friendly method of solution processing of Cu2SnS3 (CTS) absorbers using an aqueous precursor solution is presented. The precursor solution was prepared by mixing metal salts into a mixture of water and ethanol (5:1) with monoethanolamine as an additive at room temperature. Nearly carbon-free CTS films were formed by multispin coating the precursor solution and heat treating in air followed by rapid thermal annealing in S vapor atmosphere at various temperatures. Exploring the role of the annealing temperature in the phase, composition, and morphological evolution is essential for obtaining highly efficient CTS-based thin film solar cells (TFSCs). Investigations of CTS absorber layers annealed at various temperatures revealed that the annealing temperature plays an important role in further improving device properties and efficiency. A substantial improvement in device efficiency occurred only at the critical annealing temperature, which produces a compact and void-free microstructure with large grains and high crystallinity as a pure-phase absorber layer. Finally, at an annealing temperature of 600 degrees C, the CTS thin film exhibited structural, compositional, and microstructural isotropy by yielding a reproducible power conversion efficiency of 1.80%. Interestingly, CTS TFSCs exhibited good stability when stored in an air atmosphere without encapsulation at room temperature for 3 months, whereas the performance degraded slightly when subjected to accelerated aging at 80 degrees C for 100 h under normal laboratory conditions.</P>

Cu2S-Ag2S composite electrode on Ni foam for high-performance electrochemical supercapacitors

Sachin A. Pawar,Dipali S. Patil,Jae Cheol Shin 한국진공학회 2017 한국진공학회 학술발표회초록집 Vol.2017 No.2

Hexagonal sheets of Co3O4 and Co3O4-Ag for high-performance electrochemical supercapacitors

Sachin A. Pawar,디파리파틸,신재철 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-

Hexagonal sheets of Co3O4 on nickel foam were synthesized by a facile, economical, scalable, and one pot hydrothermal method for supercapacitor studies. The electrical conductivity and catalytic activity were enhanced through the decoration of Co3O4 by silver (Ag) nanoparticles using a simple chemical approach. The hexagonal sheets served as an excellent backbone together with the Ag nanoparticles, which gave the composites a superior specific capacitance of 958 F g1 and an energy density of 0.203 kWh kg1. The electrode exhibited excellent cycling stability with a capacitance retention of 104% after the initial 1000 CV cycles with a maximum specific capacitance 996 F g1.

Quantum Dot Sensitized Solar Cells Based on TiO2/AgInS2

Sachin A. Pawar,정재필,Dipali S. Patil,Vivek M. More,Rochelle S. Lee,신재철,최원준 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.10

Quantum dot heterojunctions with type-II band alignment can efficiently separate photogenerated electron-hole pairs and, hence, are useful for solar cell studies. In this study, a quantum dot sensitized solar cell (QDSSC) made of TiO2/AgInS2 is achieved to boost the photoconversion efficiency for the TiO2-based system by varying the AgInS2 layer’s thickness. The TiO2 nanorods array film is prepared by using a simple hydrothermal technique. The formation of a AgInS2 QD-sensitized TiO2-nanorod photoelectrode is carried out by successive ionic layer adsorption and reaction (SILAR) technique. The effect of the QD layer on the performance of the solar cell is studied by varying the SILAR cycles of the QD coating. The synthesized electrode materials are characterized by using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy and solar cell performances. The results indicate that the nanocrystals have effectively covered the outer surfaces of the TiO2 nanorods. The interfacial structure of quantum dots (QDs)/TiO2 is also investigated, and the growth interface is verified. A careful comparison between TiO2/AgInS2 sensitized cells reveals that the trasfer of electrons and hole proceeds efficiently, the recombination is suppressed for the optimum thickness of the QD layer and light from the entire visible spectrum is utilised. Under AM 1.5G illumination, a high photocurrent of 1.36 mAcm−2 with an improved power conversion efficiency of 0.48% is obtained. The solar cell properties of our photoanodes suggest that the TiO2 nanorod array films co-sensitized by AgInS2 nanoclusters have potential applications in solar cells.